In a breakthrough that could lead to printable organs and an enhanced understanding of human physiology, researchers from Lawrence Livermore National Labs have 3D-printed functional blood vessels that look and function like the real thing.

3D bioprinters are similar to conventional 3D printers, but instead of using inert materials, they use “bio-ink:” basic structural building blocks that are compatible with the human body.

To create the 3D-printed blood vessels, a LLNL team headed by research engineer Monica Moya combined this special biomaterial with living cells. The material and environment were designed to enable small blood vessels, or human capillaries, to develop on their own. A release from LLNL explains:

This process takes a while, so initially, tubes are printed out of cells and other biomaterials to deliver essential nutrients to the surrounding printed environment. Eventually, the self-assembled capillaries are able to connect with the bio-printed tubes and deliver nutrients to the cells on their own, enabling these structures to function like they do in the body.

“If you take this approach of co-engineering with nature you allow biology to help create the finer resolution of the printed tissue,” Moya said. “We’re leveraging the body’s ability for self-directed growth, and you end up with something that is more true to physiology. We can put the cells in an environment where they know, ‘I need to build blood vessels.’ With this technology we guide and orchestrate the biology.”